duration.cpp:96:7: error: no viable overloaded '-=' with nanotime 0.3.0 on Travis MacOS

[mattdowle]

Just seen this from Travis MacOS. (Travis Linux seems ok, and it's ok on Linux locally for me).
https://travis-ci.org/github/Rdatatable/data.table/jobs/715689511

trying URL 'https://cloud.r-project.org/src/contrib/nanotime_0.3.0.tar.gz'
Content type 'application/x-gzip' length 535610 bytes (523 KB)
==================================================
downloaded 523 KB
* installing *source* package ‘nanotime’ ...
** package ‘nanotime’ successfully unpacked and MD5 sums checked
** using staged installation
** libs
clang++ -mmacosx-version-min=10.13 -std=gnu++11 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG  -I'/Users/travis/R/Library/Rcpp/include' -I'/Users/travis/R/Library/RcppCCTZ/include' -I'/Users/travis/R/Library/RcppDate/include' -I/usr/local/include  -I../inst/include -fPIC  -Wall -g -O2  -c RcppExports.cpp -o RcppExports.o
clang++ -mmacosx-version-min=10.13 -std=gnu++11 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG  -I'/Users/travis/R/Library/Rcpp/include' -I'/Users/travis/R/Library/RcppCCTZ/include' -I'/Users/travis/R/Library/RcppDate/include' -I/usr/local/include  -I../inst/include -fPIC  -Wall -g -O2  -c duration.cpp -o duration.o
duration.cpp:96:7: error: no viable overloaded '-='
    d -= ns * std::chrono::nanoseconds(1);
    ~ ^  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode-9.4.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/chrono:578:71: note: candidate function not viable: no known conversion from 'duration<[...], ratio<[...], 1000000000>>' to 'const duration<[...], ratio<[...], 1000000>>' for 1st argument
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator-=(const duration& __d) {__rep_ -= __d.count(); return *this;}
                                                                      ^
1 error generated.
make: *** [duration.o] Error 1
ERROR: compilation failed for package ‘nanotime’
* removing ‘/Users/travis/R/Library/nanotime’
* restoring previous ‘/Users/travis/R/Library/nanotime’

[eddelbuettel]

Uh-oh. We'll take a look. And make 0.3.1 if we need to.

[eddelbuettel]

Do we know "which" clang++ that is? clang++-9 on Ubuntu works fine (modulo some warnings...).

[eddelbuettel]

Same with -10.

[lsilvest]

The issue is that std::chrono::system_cock is defined with microseconds instead of nanoseconds like on the other platforms. Not a difficult fix: I have tested it with clang under MacOS, and g++ under Ubuntu and will test on Windows in the unlikely event it causes an issue there.

[eddelbuettel]

The issue is that std::chrono::system_cock is defined with microseconds instead of nanoseconds like on the other platforms.

Ah yes. I think I once knew that too. But now I don't recall how e.g. RcppCCTZ danced around it ...